NEWARK — Two police detectives from Long Island testified today that they recovered a .357 Magnum Colt Trooper revolver while searching the home of a reputed gang member, the same weapon prosecutors say was used to fatally shoot three college-bound friends and wound a fourth at a schoolyard in 2007.

The morning testimony came at the trial of Alexander Alfaro, who is one of six young men charged in the Aug. 4, 2007, killing behind Mount Vernon School in Newark, which prosecutors say was gang-related.

Alfaro, 20, is charged with murder. Authorities say he wielded a machete to attack one of the victims, and admitted to that act on tape. Prosecutors intend to play the recording of that statement, but not today.

The black revolver with brown handle was displayed in court today during testimony from Detective Thomas Hess of the Suffolk County Police Department. “This is the firearm that we recovered," Hess told Assistant Essex County Prosecutor Thomas McTigue on the stand this morning.

Hess and another detective who also testified, Kenneth Rainey, discovered the weapon in a drawer of the Bay Shore, N.Y., home of Alvaro “Lobo” Delgadothe, a reputed member of the violent Central American gang known as MS-13.

Essex County assistant prosecutors say the defendants in the schoolyard killings all had ties to MS-13 and that the crime was committed to gain status in the organization.

Federal authorities have also linked the same gun to the May 18, 2007 killing of a Queens, N.Y. man, in which gaining status in MS-13 was also alleged to be the motivating factor, according to news reports.

The Long Island detectives’ March 24, 2008, search of Delgado’s home was unrelated to the massive investigation into the schoolyard shooting, and it wasn’t until three months later that authorities linked the weapon to the crime.

Delgado was a known MS-13 member when Long Island police searched his home that day, Hess said. On cross examination, he told defense attorney Raymond Morasse he had not heard of Alfaro, and didn’t know his alleged connection to MS-13.

At the schoolyard, Iofemi Hightower and Dashon Harvey, both 20, and Terrance Aeriel, 18, were lined up against a wall and shot in the head execution-style. They died. Terrance’s sister, Natasha Aeriel, then 19, was shot in the head but survived.

One of the defendants charged was convicted at trial last year, and the other pleaded guilty to shooting all four victims.